Which of the following is an Arrhenius base ?

Options

A. `H_2SO_4`
B. `NaOH`
C. `H_3PO_4`
D. All of these

Answer

To determine which of the following substances is an Arrhenius base, we need to understand the definition of an Arrhenius base. According to the Arrhenius theory, an Arrhenius base is a substance that, when dissolved in water, produces hydroxide ions (OH⁻).

Let's analyze the options provided:

1. **H₂SO₄ (Sulfuric Acid)**:
- When sulfuric acid dissolves in water, it dissociates to produce hydrogen ions (H⁺) and sulfate ions (SO₄²⁻).
- It does not produce hydroxide ions (OH⁻).
- Therefore, H₂SO₄ is not an Arrhenius base.

2. **Phosphoric Acid (H₃PO₄)**:
- Phosphoric acid dissociates in water to produce hydrogen ions (H⁺) and phosphate ions (PO₄³⁻).
- It also does not produce hydroxide ions (OH⁻).
- Thus, H₃PO₄ is not an Arrhenius base.

3. **Sodium Hydroxide (NaOH)**:
- Sodium hydroxide dissociates in water to produce sodium ions (Na⁺) and hydroxide ions (OH⁻).
- Since it produces hydroxide ions, NaOH qualifies as an Arrhenius base.

Based on the analysis above, the substance that is an Arrhenius base is **Sodium Hydroxide (NaOH)**.

**Final Answer**: Sodium Hydroxide (NaOH) is an Arrhenius base.

---